To support HS200 and UHS mode, mmc core will call init_card() to
execute tuning:
- sdio: init_card can be executed at runtime resume.
- sd and mmc: init_card can be executed at resume or runtime resume,
  which depends on MMC_CAP_RUNTIME_RESUME capability.

On rk3288 SoC, host will get DRTO interrupt when host send command
to read tuning data. This will spend more than 111ms:
drto_ms = drto_clks * 1000 / bus_hz = 111ms.

And the total tuning time will be more than 400ms.

So we should add MMC_CAP_RUNTIME_RESUME capability to execute tuning
at runtime resume. Only if we do so, can we pass resume test.
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>